The vast majority of roofing shingles in America are comparatively inexpensive, and are made from thin sheets of asphalt-coated building materials that are used in overlapping rows to protect the interior of a house from inclement weather. By contrast, the more expensive, “specialty” shingles have historically been constructed from a number of thicker, natural compositions, including natural slate, clay, wood and concrete. Recently, advances in polymer technology have enabled a new class of “synthetic” shingles to emerge, such that the look of more expensive natural materials can be mimicked by injection molded synthetic shingles, often at a lower total-installed cost.
Prior art synthetic shingles are typically rectangular in shape and have substantially flat top and bottom surfaces. These types of shingles are customarily installed by securing a first horizontal row, or “course,” of shingles along the bottom of the roof in a line parallel to the roofline, or “eave.” Shingles are secured independently, one shingle at a time, with what is typically a small gap or “keyway” between adjacent shingles. Also, in prior art shingles, each successive course of shingles overlays the previous course of shingles by at least 50%, so that precipitation of any kind will cascade down the roof, from one course of shingles to the next, so that water is conveyed from shingles at the top ridge of the structure down across the surface of the shingles, course after course, until it is shed from the roof safely to gutters or otherwise off of the home or building. The importance of overlapping shingles on a lower course with shingles on the next higher course by at least 50% is to ensure that water that flows down the roof structure does not trickle through the keyways between shingles in a way that would create the risk of water leaking down onto any of the underlying roof structure (underlayment materials or roof deck), which ultimately protects the valuable contents and inhabitants of any roofed structure.
Although widely accepted, prior art shingles and installation methods suffer a number of drawbacks. A large portion of each shingle is dedicated to providing the horizontal overlap needed to protect the underlying roof material from water draining into the keyways. This limits the percentage of actual exposure area provided by each prior art shingle to roughly 50% of its total size, and thereby increases the amount of roofing material actually required to successfully shed water from a roof by a factor of two. In addition, it is very difficult to maintain consistent alignment of the horizontal rows of shingles across the entire roof surface. Improper, uneven tilting of a single shingle in a way that is not exactly parallel to the eave can produce an exaggerated misalignment of subsequent adjacent shingles that are positioned with reference to the single improperly placed, uneven shingle. Accordingly, there is a need for an improved shingle that overcomes these and other deficiencies in the prior art.